Vehicle air bag systems are well known devices. Internally mounted air bags are used bags to protect a vehicle's occupants. It is also known to externally mount air bags to reduce vehicle damage in collision.
An externally mounted air bag arrangement is illustrated in U.S. Pat. No. 5,725,265 to Baber. The air bag is housed in a bumper-like chamber and is deployed when a collision is detected with the purpose of absorbing some of the force of the impact. However, because the air bag system of Baber is actuated automatically during a collision, it may also be accidentally deployed in situations where minor impacts are common, such as parallel parking in tight conditions. In addition, the Baber air bag system relies only upon the cushioning effect of the inflated air bag to reduce collision damage. Once the air bag has been deployed and begins to deflates, it provides limited or no protection from secondary impacts.
An additional drawback to collision activated systems is that the air bag is not deployed until actual contact is made between the colliding vehicles. Because the two vehicles are, by definition, touching during a collision, the expanding air bag will merely force the vehicles apart. This action can cause undesired movement in the vehicles that may result in additional collisions.
A key aspect of air-bags is that they are stored in an uninflated state. A known alternative shock absorber design is a pre-inflated rubber cell mounted to the bumper of a car. U.S. Pat. No. 5,431,463 to Chou discloses such a rubber cell which is designed to deflate upon impact to absorb shock. A compression spring is included within the cell to support the cell's forward wall. A significant drawback to this design is that it is limited in size because the shock absorbing cells are always "deployed." A large cell, with a concurrently large shock absorbing capacity, would project outward from the vehicle an unacceptable amount. Thus, the practical shock absorbing ability of such a cell is relatively small.
Accordingly, is an object of the invention to provide a vehicle air bag system which is compact and which can be pre-deployed by a vehicle operator before a collision.
It is a further object of the invention to provide an external air bag assembly which is affective in absorbing the force of both primary and secondary impacts.
Yet another object of the invention is to provide an air bag arrangement that is easy to reset after deployment.